README: Remove "Test fixes for Git 2.5.x/git log %d" to-do item
README: Remove "Test fixes for Git 2.5.x/git log %d" to-do item

This was probably referring to the fix long ago in commit 502be05 (njr
2015-08-05), added shortly after this to-do item. We've been using
this on much newer versions of Git for a long time now, so I guess it
works. Tested just now on Git 2.11.0.

cjs-cynic-net/git-commit-filetree,cjs-cynic-net/git-commit-filetree,cjs-cynic-net/git-commit-filetree